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13,. P. THOMPSON. PROCESS OF TREATING FILAMENTS FOR INGANDESGENT ELEGTRIG LAMPS.

Patented Oct. 4, 1 887 Evan/whom $51 1 Fo'i/y abbomwl a N, PETERSJPhokoLilhugrapher. Wnhinglun. nc

VUN'ITED STATES PATENT OFFICE.

EDWARD P. THOMPSON, or ELIZABETH, NEW JERsEY.

PROCESS OF TREATING FILAMENTS FOR INCANDESCENT ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 371.002, dated October 4. 1887.

Application filed February 4, 1887. Serial No. 226.528.

ments for Incandescent Electric Lamps, of

which the following is a specification.

The invention relates to a method of treating carbonized filaments for incandescent electric lamps before they are inserted in the lamps, the object being to remove the oxygen gas therefrom and supplant the same by some inert gassuch, for instance, as hydrogen. The advantage secured is that when the filaments are allowed to retain oxygen after they are placed in the lamp and are heated during the process of exhausting, the heat will cause the oxygen to attack the carbon and injure the same to a greater or less extent. By supplanting the same by hydrogen gas this result is avoided.

The invention will be described in connection with the accompanying drawings, in which- Figure 1 is asection of a vessel suited to be employed in the treatment of the filaments, and Fig. 2 is a similar view, illustrating the second step.

Referring to the figures, A represents a containing-vessel of any suitable character, preferably provided with a cover, B, fitting tightly thereon. Within this vessel the filaments to be treated are placed. They are covered by a hydrocarbon liquid-such, for instance, as naphtha, as shown at C. An exhaust-pipe, d, is employed for withdrawing or rarefying the atmosphere above the liquid. By this means the oxygen contained in the pores of the filament will gradually be withdrawn,passing in bubbles to the surface of the liquid and then being withdrawn from the vessel. In this manner practically all the oxygen will be withdrawn from the filaments. The next step in the operation is to withdraw the liquid from the vessel A,or else place the filaments in an- (No model.)

other similar vessel, as shown at A in Fig. 2. This vessel is covered, and, if necessary, the lid B is fastened down by a weight, B, or in any other convenient manner,forming a tight joint between the ground edges of the vessel and the cover. The filaments are then heatedas,for instance, by a flame, F, placed beneath the vesseland this causes the hydrocarbon liquid which may remain upon the filaments to be vaporized and to pass over into a flask,

G, where it condenses. After the filaments are sufficiently dry, hydrogen or other equivalent gas is supplied to the vessel A through a pipe, h, provided with a stop-cock, h. This gas will enter the vessel A and fill the pores of the filaments, which are then ready to be placed in the lamps.

A filament thus prepared will not be injured by the heating to which it is subjected during the process of exhausting the lamp.

I claim as my invention-- l. The hereinbefore-described process of treating filaments, which consists in supplanting the oxygen by a hydrocarbon liquid and subsequently supplanting the hydrocarbon liquid by hydrogen gas, substantially as described.

2. The hereinbeforedescribed process of treating carbonized filaments, which consists in immersing them in a liquid free from oxygen and subsequently removing the liquid and filling the pores with an inert gas.

3. The hereinbefore described process of treating filaments, which consists in immersing the same in a hydrocarbon liquid, and thereby withdrawing the oxygen from the filaments, subsequently drying the filaments and surrounding them by an atmosphere of hydrogen, substantially as described.

In testimony whereof I have hereunto sub scribed my name this 21st day of January, A. D. 1887.

EDWARD P. THOMPSON.

Witnesses:

DANL. W. EDGECOMB, CHARLES A. TERRY. 

